This invention relates to a mechanically actuatable disc brake.
A disc brake is known from German patent specification DE-A No. 3 142 799 which includes a rotational ratchet mechanism which is operative when the actuating shaft is turned in the release direction. With this known disc brake the adjustment of the clearance therefore takes place during the brake release process. This principle is, however, not fully satisfactory as it is not possible to exclude unintentional adjustment of the clearance as a consequence of elastic deformation of the brake components, for example of the brake caliper, on the occurrence of very high braking moments. An incorrect adjustment of the clearance would, however, have the effect that after termination of the braking process unwanted frictional moments would appear between the brake disc and the brake linings and lead to severe heating of the entire brake unit. There is therefore a need for a disc brake in which unintentional adjustment of the clearance as a result of elastic deformation of the brake components can be excluded with certainty.
A sliding-caliper disc brake is also known from German Patent Specification No. DE-C 2 330 949 in which the adjustment of the clearance is carried out, not during the brake release process, but infinitely variably and as a function of the force during the actuation of the brake, arrangements being made to exclude any unintentional adjustment of the clearance as a consequence of the elastic deformation of the brake caliper occurring at very high braking moments. However, this known principle is only applicable to hydraulically actuated disc brakes.